Re: [PATCH] xen: unexport __init-annotated xen_xlate_map_ballooned_pages()

[Juergen Gross <jgross@xxxxxxxx>]

On 06.06.22 06:59, Masahiro Yamada wrote:
> EXPORT_SYMBOL and __init is a bad combination because the .init.text
> section is freed up after the initialization. Hence, modules cannot
> use symbols annotated __init. The access to a freed symbol may end up
> with kernel panic.
>
> modpost used to detect it, but it has been broken for a decade.
>
> Recently, I fixed modpost so it started to warn it again, then this
> showed up in linux-next builds.
>
> There are two ways to fix it:
>
>    - Remove __init
>    - Remove EXPORT_SYMBOL
>
> I chose the latter for this case because none of the in-tree call-sites
> (arch/arm/xen/enlighten.c, arch/x86/xen/grant-table.c) is compiled as
> modular.
>
> Fixes: 243848fc018c ("xen/grant-table: Move xlated_setup_gnttab_pages to common 
> place")
> Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Pushed to xen/tip.git for-linus-5.19a


Juergen

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